New Chain tensioner still rattles

[88M6]

Have a 2002 540 just turned 100k and upon cold startup has the rattle for 1-2 seconds.
pirchased INA tensioner and pulled old one out and old spring is same updated length as new INA one,not shorter version like I had in my other 2002 540 originally.(replaced that with new updated spring n now quiet)
Now 2cold startups n same 1-2 second rattle.

What am I looking at here? Am I doomed to guide replacement at this early life? Why is it rattling with new updated tensioner.?( I purchased at 82k n has had the rattle off n on since n I never changed tensioner til now. So don't know if one I took out was replacement or has been in there since new. 10/02 production)
TIA

[TheAngryBear]

There are a few different things going on that cause distinct possibilities, each contributes and thus makes it impossible to tell when the guides are going to fail.
1) Total engine operating hours: longer the engine operates the longer the wear on all the elements. This includes the guides but also the check valves (more on this later).
2) Age of components: regardless of use, your guides and components are 15+ years old. Time will take its toll.
3) Engine operation "quality": thrashing it shortens lifespan as does "soccer mom syndrome", oil/gas quality, and a host of other items.
4) Ambient conditions: environmental conditions will impact (dry and dusty vs cold and wet vs combinations).

All of those over the life of the vehicle will cause different wear patterns and issues. Bad thing? No but anyone that says only at X mileage is "wrong".

Personally I think the oil check valves are "to blame". Oil drains out and for the first two seconds you get the noise. Annoying at times but not the worst in the world. See the list above and determine which is the biggest impact, I certainly don't know.

So what to do:
1) tear everything down and replace everything (you could do just the check valves but while you are there...) Probably won't solve long term. I did this at 160k and have the "start rattle" 1 in 5 times.
2) try and adjust the tensioner and see if it is a hair off. Maybe but not likely.
3) live with it until it gets worse or you have a likely or actual issue.

Your choice.


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[Mach540]

What am I looking at here? Am I doomed to guide replacement at this early life? Why is it rattling with new updated tensioner.?
TIA

Basically, the tensioner has little to do with the rattle. Online folklore has lead many to think that it does. So you are not alone there.

The rattle is most likely caused by oil bleed out from the VANOS gears, which lets the cam waggle about until the pressure is built back up.
Noisy, but apparently not harmful.

Guide replacement is a totally separate issue.

[JimLev]

Basically, the tensioner has NOTHING to do with the rattle. Online folklore has lead many to think that it does. So you are not alone there.

The rattle is most likely caused by oil bleed out from the VANOS gears, which lets the cam waggle about until the pressure is built back up.
Noisy, but apparently not harmful.

Guide replacement is a totally separate issue.

100% correct. A few years ago I replaced my guides (130K ??) and still had the rattle but only 1 out of 10 starts and never when the engine was hot. The check valves behind the vanos solenoids were fine.
The following year I changed the vanos orings, haven't had a rattle since.
You might as well do both jobs at the same time so you'll only need to time the engine once.

[88M6]

Thanks for education !
also, so I just changed tensioner like mentioned previous post in my 540/6 (93k)and tha rattle has gone away on startup but according to posts it's more likely to return and is a vanos issue on both cars that will have to be dealt with down the road upon more frequent rattling?
starting to think have two around same miles may not have been a good idea. Many repairs will be x2. Yikes

[lesguy]

had my guides replaced, tensioner, AND vanos rebuilt with Beisan system. That was about 2 years and about 25k miles ago? Still get the occassional, random startup rattle. And not always on cold start. May or may not rattle on first start of day, may or may not rattle when starting after the engine is fully warmed for the day. either way, engine still runs perfectly fine.

[JimLev]

Lesguy, did you pull out the check valves behind the vanos solenoids to make sure they were clean and not stuck open?

[lesguy]

Hi Jim..at the time, a noted independent that has a pretty good reputation with BMW's, did the job. Mechanic was a long time BMW dealership mechanic before leaving. I would have hoped he checked..but I cant say Im certain that he did..

[dannyzabolotny]

Honestly, the rattle never fully goes away. On all of the M62tu's that I've rebuilt, I've replaced the chains, guides, Vanos seals, tensioners, and check valves. Even after all of that there's still an occasional cold start rattle. That's just the way these engines are designed. You just learn to live with it.

I wouldn't worry about your guides until you get a continuous rattle noise while running the engine— then you know the guides are toast.

[Mach540]

Has anyone ever reported start up rattle on a Non-VANOS engine??

Pretty much the same TC system, is it not?